Implantable Antennas for Biomedical Applications

1. Implantable Antennas for Biomedical
Applications
Dr. Ashok Kumar Srinivasan
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2. 1/19/2024 2
Constantine A. Balanis
Dr. T. Shanmuganantham, Pondicherry University

3. 1/19/2024 3

4. 1/19/2024 4
Chicken 65
Chicken Leg piece
Dielectric Constant
Concept
Fish Curry

5. Contents
1. Biomedical Applications
2. Implantable Antenna
3. Frequency Bands
4. Motivation
5. Methodology
6. Results and Discussion
7. Wearable Antenna
8. Cell Phone Radiation
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6. 1. Biomedical applications
▪ Glucose monitor
▪ Retinal prosthesis
▪ Cardio paces
▪ Blood pressure monitor
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7. Biotelemetry System
Measurements
Temperature
ECG - Heart Rate
EMG - Muscle Rate
EOG - Retinal
EEG - Brain wave
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8. ▪ Use in biomedical therapy and monitor various
physiological parameters.
▪ Build wireless communication links between
implantable devices and exterior instruments.
▪ Communication links between medical sensors and
exterior instruments for short range biotelemetry
applications.
▪ Needs low complexity, small size and low power
consumption.
2. Implantable Antenna
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9. ▪ MICS band frequency of 402-405MHz.
▪ ISM Band frequency of 433 MHz,
915 MHz,
2.45 GHz and
5.8 GHz
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10. Name Band [MHz] Max. Tx Power [dBm EIRP] Comments
MICS 402.0 – 405.0 -16 Worldwide
ISM 433.1 – 434.8 +7.85 Europe
ISM 868.0 – 868.6 +11.85 Europe
ISM 902.8 – 928.0 +36 w/spreading Not in Europe
ISM 2400.0 – 2483.5 +36 w/spreading Worldwide
ISM 5725.0 – 5875.0 +36 w/spreading Worldwide
WMTS 608.0 – 614.0 +10.8 US only
WMTS 1395.0 – 1400.0 +22.2 US only
WMTS 1427.0 – 1432.0 +22.2 US only
UWB 100.0 – 960.0 US only
UWB 3100.0 – 10600.0 US, UK and Singapore
3. Frequency Bands
Table 1 Unlicensed frequencies available for in body communication
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11. Challenges
▪ Biocompatibility
▪ Miniaturization
▪ Restricted power incident
▪ Low Power Consumption
▪ Communication link characteristics
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12. Fig.4.1 Hospital Environments
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4. MOTIVATION

13. Fig.4.2 Signal transferring to responsible person
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14. Fig.4.3 Implantable antenna for heart rate measurements
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15. 5. METHODOLOGY
5.1 Body Simulating Fluid
5.2 Pork Tissue
5.3 Human Body Phantom Liquid
5.4 Antenna Design
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16. Order Reagent
BSF
1000 mL 2000 mL
0 Ultra-pure water 750 mL 1500 mL
1 NaCl 7.996 g 15.92 g
2 NaHCO3 0.350 g 0.700 g
3 KCl 0.224 g 0.448 g
4 K2HPO4・3H2O 0.228 g 0.456 g
5 MgCl2・6H2O 0.305 g 0.610 g
6 1 kmol/m3 HCl 40 cm3 80 cm3
7 CaCl2 0.278 g 0.556 g
8 Na2SO4 0.071 g 0.142 g
9 (CH2OH)3CNH2 6.057 g 12.14 g
10 1 kmol/m3 HCl Appropriate amount for adjusting pH
5.1 BODY SIMULATING FLUID
Table 5.1.1 Preparation of BSF
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17. Fig.5.1.1 Body Simulation Fluid
(a) without mixing HCL (b) with HCL
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18. Fig.5.2.1 Collection of live pork tissue
5.2 Pork Tissue
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19. Fig.5.2.3 Electrical Properties of pork tissue at 2.45GHz (a) permittivity (b) conductivity.
Fig.5.2.2 Dielectric measurement (Pork tissue)
(a) (b)
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20. Tissue Shape State Ingredients
Permittivity &
Conductivity
Ref
Skin Rectangular Gel
Deionized water,
Sugar, agarose
εr = 38, [7]
Scalp Rectangular Gel
Water, salt,
acrylamide, TMEDA,
ammonium per
sulphate.
εr = 28 [9]
Rat Tissue Rectangular Gel
Deionized water,
DGBE, Triton X-100
εr = 45.2 [14]
Skin
Muscle
Fat
Rectangular Gel
Deionized water,
sugar deionized
water, salt, vegetable
oil, flour deionized
water, sugar, salt
εr = 38
εr = 52.7
εr = 5.28
[15]
Table 5.3.1 Phantoms used for testing of implantable antennas
5.3 Human Body Phantom Liquid
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21. Ingredients Skin Fat Muscle
Deionized Water 50% 2.9% 59.5%
NaCl - 0.1% 0.5%
Sugar 50% - 40%
Vegetable oil - 30% -
Flour - 67% -
Table 5.3.2 Preparation of human body phantoms
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22. Fig.5.3.1 Muscle, Skin and Fat Phantom Liquid Fig.5.3.2 Skin tissue phantom liquid
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23. Need for CPW
– Most popular in air environments.
– Few implanted antennas are designed.
– Less dispersion
– Low conductor loss
– Low radiation loss
5.4 Antenna Design Methodology
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24. Features
– Wide bandwidth
– Better impedance matching
– Easy integration with passive & active devices with
monolithic microwave integrated circuits.
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• Microstrip Antenna
• PIFA Antenna

25. 6. EM Simulator
1/19/2024 25

26. 1/19/2024 26
Simulation model setup

27. 7. Results and Discussion
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28. 7.1 CPW fed crossed bowtie antenna
Fig.7.1.1 Antenna Structure (Dimensions are in mm)
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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29. Fig.7.1.3 Simplified equivalent circuit of Fig.7.1.2
Fig.7.1.2 Equivalent Circuit of proposed antenna
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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30. International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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31. Fig.7.1.4 Return Loss Characteristics
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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32. Analytical Model Flowchart
Fig.7.1.5 Flow chart
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
START
Select Dielectric Material
tan and Thickness
Develop a network model of
proposed antenna
Perform input impedance
Extract S-Parameter Vs
Frequency
If
The Frequency Response
acceptable
STOP
YES
NO
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33. Fig. 7.1.6 Analysis Results
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
(b) Contour region
(a) Boundary model
(c) antenna radiation (d) Radiation View
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34. Fig.7.1.8 Measurement setup
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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35. Fig.7.1.9 Measurement setup
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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36. Fig.7.1.10 Return Loss Characteristics
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
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Fig.7.1.11 VSWR characteristics

37. Fig.7.1.12 Radiation Pattern
International Journal of Electronics and Communication, Elsevier Publications, Vol.68, 2/2014, pp.158-165
(a) H-Plane Co Polarization (b) H-Plane Cross Polarization
(c) E-Plane Co Polarization
(d) H-Plane Cross Polarization
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38. 1/19/2024 38
Fig.7.1.13 Antenna Gain
-5dBi
3dBi

39. Fig.7.2.1 Proposed Antenna Structure Dimensions are in mm
Telemedicine and e- Health, Mary Ann Liebert, Inc. Vol.20 No.3, March 2014 .
7.2 CPW fed X Shaped Monopole Antenna
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40. Fig.7.2.2 Equivalent circuit of proposed antenna
Telemedicine and e- Health, Mary Ann Liebert, Inc. Vol.20 No.3, March 2014 .
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41.  
)
//(
)
//
//
(
// 7
6
5
4
3
2
1 Z
Z
Z
Z
Z
Z
Z
Zin +
+
=
Reflection coefficient,
0
0
z
z
z
z
k
in
in
+
−
=
VSWR =
k
k
−
+
1
1
2
1
log
10
k
)
log(
20 k
−
Return loss =
Numerical Calculations
Telemedicine and e- Health, Mary Ann Liebert, Inc. Vol.20 No.3, March 2014 .
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42. Fig.7.2.3 Return Loss Characteristics
Telemedicine and e- Health, Mary Ann Liebert, Inc. Vol.20 No.3, March 2014 .
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43. Fig.7.2.6 Prototype X Shaped Monopole Antenna
Telemedicine and e- Health, Mary Ann Liebert, Inc. Vol.20 No.3, March 2014 .
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44. 44
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Some more Examples

45. 45
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Fig. Measurement Setup

46. 1/19/2024 46
Fig. Measurement Setup

47. Proposed Antenna
Name
Volume
(mm3)
Substrate Frequency
Return
Loss (dB)
Gain
(dBi)
CPW fed Dual V
Shaped 600.6 FR4
915 MHz
2.45 GHz
-13.5
-24
-23
-16
CPW fed Crossed
Bowtie 371.8
Alumina
Ceramic
2.45 GHz -21 -6.5
CPW fed
Rectangular Shaped 238.8 FR4 2.45 GHz -27 -7
CPW fed Crossed
Type Triangular Slot
78
Alumina
Ceramic
2.45 GHz -19 -6
CPW fed H-Slot
Monopole
71.5
Alumina
Ceramic
2.45 GHz -14 -12
CPW fed
X- Monopole
67.6
Alumina
Ceramic
2.45 GHz -20 -17
CPW fed Z-
Monopole
38.675
Alumina
Ceramic
2.45 GHz -30 -14
Table 7.1 Overall Comparison of Proposed Antenna Results
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48. 8. Wearable, Textile and Flexible Antennas
Printing and Embroidering
Conductive Plastics & Metallic Yarns

49. Why Body-Centric Wireless Comms?
• Wearable computers
used in various
applications such as:
– Military
– Healthcare
– Sport
– Education
– Industrial control
– Research
– Fashion
Wearable computers courtesy of Xybernaut, Germany

50. Motivation
Medical (Elderly Home, ICU, ...) Personal Communication
(Smart Phones, GPS, ...)
Tharaka Dissanayake, et. al.
Integrate antennas and RF devices into clothes or human body
Lanlin Zhang, et. al.

51. Embroidering onto Fabric
Lanlin Zhang, et. al.
Transmission Line
Lanlin Zhang, et. al.
WiFi System RFID Antenna
Karoliina Koski, et. al.
Characterise, design and test new antennas and RF devices, and
influence from/to human body
Electric field strength with/without shielding.
Radiation pattern
of antenna
placed on chest

52. Radiation from a stomach implanted
device
• Using different digital
phantom to highlight
subject-specific
propagation characteristics
188
cm
173
cm 161
cm
Hugo American
model
Japanese male
model
Japanese female
model
188
cm
173
cm 161
cm
Hugo American
model
Japanese male
model
Japanese female
model
◆ Radiation performance is
different due to varying
distribution oh lossy
human tissues

53. Experimental Investigations

54. 54
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